• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2335-2343
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• 2018

This paper proposes an optimal damping control algorithm of the DTI (Direct Two-level Inverter) to miniaturize and reduce the weight of auxiliary power supply for railway vehicles. The conventional auxiliary power supply for railway vehicles uses a DC-DC converter to maintain the inverter input power from the line voltage smoothly. The proposed topology does not use a DC-DC converter for reducing of manufacturing and maintenance costs. It also proposes a DTI topology removed damping resistors that generate ground signal noise in a certain period. At this time, a resonance phenomenon of DC-link voltage occurs due to variation of the inductive load, and a method of controlling the resonance phenomenon of DC-link voltage is required. In order to suppress the resonance phenomenon of the DC-link voltage, at a point before resonance occurs, this paper introduces an algorithm to suppress the resonance phenomenon of DC-link voltage by compensating the resonance component of the q axis voltage of the synchronous reference frame. The proposed algorithm verifies the effect through simulation and experiment.

• 조명전기설비학회논문지
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• 제24권6호
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• pp.160-168
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• 2010

본 논문은 직류전기철도 급전시스템에서 누설전류와 변전소로부터 공급되는 전류의 분포에 대하여 다루었다. 일반적으로 직류전기철도 급전시스템에서는 운행용 레일을 귀로 전류(부극성)의 도체로 사용하고 있으며, 이러한 조건은 추가적인 도체의 설치를 필요로 하지 않기 때문에 경제성을 고려한 것이다. 그러나 운행용 레일과 대지 사이의 저항이 작은 경우에는 대지로 흐르는 누설전류가 문제가 된다. 이 누설전류는 레일 주변에 설치된 지하 매설물에 영향을 미치며, 인체의 안전과도 관련이 있다. 따라서 직류전기철도 급전시스템에서 누설전류를 억제하는 것은 차량의 운전이나 안전 측면에서 중요한 문제이다. 본 논문에서는 직류전기철도 급전시스템에 대하여 CDEGS의 SPLIT 프로그램을 이용하여 레일의 전류분포를 시뮬레이션하였고, 레일의 누설저항 크기에 따른 누설전류 변동치를 도출하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.91-94
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• 2003

A DC railway system has low feeder voltage, The fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases all at once. So the type of ${\Delta}I$ relay(50F) was developed using the different characteristics between the load starting current and the fault current. As for the load starting current, the time constant of load current at each step is much smaller than that of the fault current. First, to detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares is presented in this paper. Secondly, to compose a protection scheme for DC railway systems is presented in this paper.

• 전기학회논문지
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• 제66권4호
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• pp.733-739
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• 2017

Research on fuel cell systems attracting attention as an environmentally friendly energy source has been actively conducted. And research is being conducted on railway vehicles that use direct current power generated by a fuel cell as an energy source. In this paper, a two-phase interleaved bidirectional DC-DC converter has been proposed which can supply electric energy of a battery to a traction motor during powering and charge the battery with regenerative energy during braking. Therefore, the topology of the energy storage system applied to the railway vehicle was analyzed, and the simulation was performed by constructing the power conversion system by this topology. Experiments were also conducted through hardware design and fabrication based on the simulation analysis results, and the validity of the hardware implementation was verified.

• 전기학회논문지
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• 제63권8호
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• pp.1159-1163
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• 2014

This paper have been dealt with the analysis for energy efficiency improvement effect of unity storage capacity as a part of the energy storage application study to improve energy efficiency in the electric railway systems. Especially, in order to estimate the amount of energy saving according to the variation of power capacity of each storage, the current limit module was mounted on an existing DC electric railway loadflow program which is based on the analysis model for railway system and storages, and combined optimization algorithm to determine optimal voltage boundary.

• 대한전기학회논문지:전력기술부문A
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• 제55권11호
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• pp.463-467
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• 2006

A direct current electric power system is one of the most important power source in a metro railway system. As railway system is growing up today, the importance of DC electric power system is emphasized. The study for systemization and standardization of design and operation technique in DC electric power system is undergoing nowadays. For these studies, the development of standard analysis model for metro railway electric power system is required. In this paper, a standard analysis model for metro railway electric power system which is using PSCAD/EMTDC program is proposed. The proposed model is explained and the validity is shown by using the case studies.

• 한국철도학회지
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• 제8권4호
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• pp.11-19
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• 2005

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1597-1598
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• 2015

Regenerative power utilization is one of the most interesting issue in electric railway systems. Generally, technologies to utilize regenerative power from railway vehicles are railway substation with regenerative inverter, on-station energy storage systems, and on-board energy storage systems. In this paper, the electric power loss for those technologies is calculated and compared using DC electric railway system analysis algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.3-5
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• 2002

If a fault occurs in the DC railway system, it is important to find fault location and to remove it immediately for prompt repair. The aim of the present paper is to locate the position of the fault by using Kirchhoff's voltage law(KVL). The DC railway system is simulated using Power System Blockset(PSB) in Matlab Toolbox.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.14-16
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• 2004

A DC railway system has low feeder voltage, The remote fault current can be smaller than the current of load starting. So it is important to discriminate between the small fault current and the load starting current. The load starting current increases step by step but the fault current increases all at once. As for the load starting current, the time constant of load current at each step is much smaller than that of the fault current. To detect faults in DC railway systems, an algorithm using the time constant calculated by the method of least squares was presented. But, It have a weakness about harmonic to calculate time constant. So in this paper, new protection algorithm for DC railway systems using estimation of time constant based on fourier transform was presented.